1. Field of the Invention
The invention relates generally to fastening devices for round holes and notably to fastening devices of plastics material designed to receive screws for assembling parts to supports.
2. Description of the Prior Art
The problem with prior art types of fastening devices of this type is to prevent their rotation during assembly. To this end it is customary to form openings other than round in the supports.
When the opening is round, it is known at the present time, to fix the fastening members, to glue them to the supports by adhesive or again to prevent their rotation, by the use either of a rough surface or of stubs. More recently, solutions by eccentricity of the screw have been suggested but they do not give entire satisfaction.
It is an object therefore of the present invention to provide a fastening device of plastics material for a round hole, designed to receive a screw, without eccentricity nor immobilization, and this in such a way that it permits mounting with a high gripping torque and this even in thin sheet metal or parts of little thickness.